Muffler can

ABSTRACT

This invention relates to a muffler can for use in the muffling of devices such as compressors for air conditioning units. The novelty of the device consists of the manner in which the resistance path for the exhaust fluids is arranged. It consists essentially of a series of baffle paths within a can which are formed by tubular extensions from each of the end walls of the can. Each of the tubular baffles originates with a wall and stops short of the opposite wall. All tubular baffles have a substantial portion of their extent coextensive with all others so that in effect a series of interconnected baffle paths is formed in the casing that progresses in a radial direction from the center baffle.

United States Patent Inventor Otto E. Ilieder Etobicoke, Ontario, Canada Appl. No. 881,192 Filed Dec. 1, 1969 Patented Oct. 12, 1971 Assignee General Impact Extrusions (Manufacturing) Ltd. Tomato, Ontario, Canada MUFFLER CAN 1 Claim, 4 Drawing Figs. A US. Cl 181/53, 181/61, 181/35 C Int. Cl Wln 1/08, FOln 7/18 FleldotSearch 181/49,53, 54, 60, 61- 63 References Cited UNITED STATES PATENTS 5/1962 Abbuhl 181/56 Primary Examiner-Robert S. Ward, Jr. Attorney-Fetherstonhaugh & Co.

ABSTRACT: This invention relates to a muffler can for use in the muffling of devices such as compressors for air conditioning units. The novelty of the device consists of the manner in which the resistance path for the exhaust fluids is arranged. It consists essentially of a series of baffle paths within a can which are formed by tubular extensions from each of the end walls of the can. Each of the tubular baffles originates with a wall and stops short of the opposite wall. All tubular baffles have a substantial portion of their extent coextensive with all others so that in effect a series of interconnected bafile paths is formed in the casing that progresses in a radial direction from the center baffle.

MUFFLER CAN This invention relates to muffler cans and is particularly concerned with a muffler can of the type used in small air conditioning units, such as those employed in automobiles.

The term muffler can" is a trade term referring to noise suppressors, often simply called "mufflers." Such devices essentially consist of closed boxes having an inlet and an outlet and containing a plurality of internal baffles to provide back pressure to the gases or fluids passing through the muffler from the engine, compressor or other source involved.

The traditional way of making a muffler is to build up a baffle arrangement within a canister by attaching, by welding for example, a number of baffle elements to each side surface of the canister. In the result, the completed article is made up of a large number of separate parts and the labor and time involved in bringing together and connecting these parts are the major cost items in the manufacturing cost.

It is, therefore, a chief object of this invention to provide a muffler which can be manufactured at relatively low cost compared to muffler cans heretofore available.

It is a more specific object of this invention to provide a muffler can that is comprised of relatively few parts compared to muffler cans known heretofore.

With the above and further objects in mind, a mufiler can in accordance with the present invention comprises a casing having diametrically opposed end walls and a sidewall with a plurality of tubular baffle walls that extend from one or other of the end walls and terminate short of the opposite end wall. The baffle walls form a series of interconnected baffle paths within the casing. An inlet and an outlet opening is provided to the casing to provide access to the series of baffle paths for the gases or fluids from the engine, compressor or other source involved.

The invention will be more thoroughly understood from the following description of several preferred embodiments thereof as read in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a longitudinal cross-sectional view through a first preferred embodiment of the invention;

FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a side elevation view partly in section of a die and punch assembly for an impact extrusion machine adapted to the manufacture of one of the can components making up the muffler can of FIGS. 1 and 2; and

FIG. 4 is a view similar to FIG. 1 of a second preferred embodiment of the invention.

Referring to FIG. 1, the muffler can illustrated is particularly adapted for use in automotive air conditioning assemblies and has an overall length of about 18 inches with the muffler can per se having a length of about 6 inches and a diameter in the order of about 3%inches. It should be understood, however, that these dimensions are given only by way of example and, further, it should be understood that the utility of the muffler can of the invention is by no means restricted to use in automotive air conditioning assemblies.

The muffler can illustrated in FIG. 1 is made of only three separate parts. These are a first can component 10 having an integral inlet or outlet pipe 11, a second can component 12 and an inlet or outlet pipe 13. Having in mind the intended use of the particular muffler can illustrated, it is formed of an aluminum alloy, but for other uses, the can could be formed of other materials, for example, steel.

The two can components 10 and 12 are formed by impact extrusion from slugs. A punch and die assembly for producing component 10 is shown in FIG. 3.

Component 10 includes end wall 16, the integral inlet or outlet pipe ll previously mentioned, a bafi'le wall lla, an outer or sidewall 20 and a coaxial tubelike baffle wall 22. The second can component 12 is comprised of an end wall 24, an outer or sidewall 26 and two tubelike baffle walls 28 and 30 respectively. The third component, namely, inlet or outlet pipe 13, is fixed to end wall 24 of component 12 at an aperture 32 in end wall 24 as by welding or the like. It should be noted that this third component, pipe 13, can by thesame impact extrusion method, be integral with end wall 16, creating a twopart can requiring only minimal rearrangement of the internal bafiles to provide the same performance as a three-part can. The choice between twoor threepart construction rests with the user, depending on the specific application, and both alternatives are within the scope of this invention.

As can be seen in FIG. 1, each ofthe baffle walls Ila, 22, 28 and 30, as well as the inner end of integral pipe II, are dimensionedso that their free ends are spaced somewhat from the inside surface of the other can component end of the can casing that they approach. It can be seen, therefore, that the cooling medium from the source in the case of a cooling unit of an air conditioner takes a circuitous route through the muffler can through a continuous series of interconnected baffle paths that progresses radially outwardly of the first path in the series (along tube 1 la) to the last path in the series (the one defined by walls 28 and 26), and the total length of these paths can be varied by increasing or decreasing the spacing between the free ends of the baffle walls and their respective end walls. This is not to suggest that such a variation is possible within any one mufi'ler, but refers to the fact that with this one basic muffler configuration, it is possible to produce mufflers of variable muffling action in orderto meet the different muffler requirements of various pieces of equipment in various applications.

Following impact extrusion, the assembly of a complete muffler can is a relatively simple matter and merely amounts to telescoping the two can components together, using an epoxy bonding compound between the two outer walls and then to weld or braze or otherwise secure inlet or outlet pipe 13 to the second can component 12. It will be understood, of course, that the bonding of the two can components together by an epoxy cement is a preferred expedient and that other suitable means could be used for accomplishing this connection. In the case of a two-part muffler can, as previously described, the integral inlet and outlet pipes eliminate the necessity of welding, brazing or otherwise securing pipe 13 to can component 12.

FIG. 4 illustrates the modification, previously mentioned, wherein pipe 13 is fonned integrally with end wall [6. As shown in FIG. 4, this integral pipe I30 would normally be located so as to connect with the radially outermost baffle path but, as previously explained, with respect to the separate piece pipe 13, it could be located radially inward of the illustrated position.

FIG. 4 also illustrates another modification in which two inlet or outlet pipes are connected to one end wall enabling the user to choose between a muffler can with inlet and outlet pipes either at one end of the can or with the inlet at one end and the outlet at the opposing end of the muffler can. Thus, a second inlet or outlet pipe 15 is connected to end wall It). When pipe 15 is used, the pipe 13a would be closed off or if the user elects to use pipes 11 and 13a, pipe 15 would be closed off. Pipe 15 is shown as being formed integrally with end wall 16, but it would be within the scope of the invention to use a separate pieces as can be done in the case of pipes 11 and 13. The pipe 15 could also be located radially inward of the illustrated position.

The punch and die assembly illustrated in FIG. 3 essentially consists of a die 40 and a punch 42 with the latter including a central pin 44. Actually punch 42 is made up of a punch head 46 and a punch head sleeve 48. The die end of the illustrated assembly includes a die insert 50, an inner shrink ring 52 and an outer shrink ring 54.

As will be appreciated by those familiar with impact extrusion equipment, the slug is placed against the die 40 within the confines of the die insert 50 and the punch and punch pin assembly is forcibly rammed against the slug so that the material of which the slug is formed flows back over the punch to produce the outer wall 20, the baffle wall 22 and the inner portion of the integral pipe 110, while the punch pin 44 carries forward from the central area of the slug a certain amount of material which is formed into the outer part of pipe 11. With modifications to the punch and die, a second integral pipe similar to pipe 11 can also be formed at the same time, allowing the final two-component muffler can already described herein.

As will also be understood by those familiar with impact punching processes, the amount of flow of material varies somewhat from slug to slug so that an excess of material is used and the outer wall, baffle wall and pipe 18 are later trimmed off to give the desired length. It is at this trimming stage that the length of the baffle'walls is selected to meet the particular design requirements of the apparatus to which the muffler involved will be attached.-

It should also be understood that while the particular muffler can illustrated has four tubelike baffles (including the inner end 11a of pipe 11), it is within the scope of the invention to use more or less baffles. Further, it is within the scope of the invention to attach the inlet or outlet pipe 13 to an aperture located radially inward of the position of the illustrated aperture 32. This would be one way of reducing the path of travel of the coolant, gas or fluid through the muffler can and, although a can modified in this way would have excess potential capacity, it might be less expensive to meet a smaller muffler requirement in this way than by modifying the die and punch or the baffle trimming equipment. Moreover the sidewall of the can which is composed of tubular extensions 26 and 20 could be formed from a single tubular extension from one end wall, in which case the other end wall would fit on the free end of the tubular extrusion. The sidewall could even be separately formed. The important thing is the formation of a series of baffle paths within a can by tubular extensions of the end walls; while in the optimum design one inlet connection will be to the first path in the series and the other connection will be to the last path in the series, it is practical to make the inlet and the outlet to other than the first or the last path in the series. The latter construction would probably only be used as a convenience in using a standard mufi'ler can for several applications.

In use, the twoor three-part mufiler can is connected, in the case of an automobile air conditioner, within the system or coolant circuit and the series of paths formed by the baffle walls exerts the desired back pressure to quieten the operation. Exact choice of location within the system will depend on the muffling requirements of the particular system. It will be appreciated that the mufiling effect is a function of the path dimension and that this can be varied as required in accordance with known principles. The simplified construction of the mufiler can is the novel and beneficial feature of this invention. v

What I claim as my invention:

1. A muffler can comprising an outer casing having a first end wall, a second end wall, a first tubular sidewall and a second tubular sidewall, said first tubular sidewall being formed integrally with said first end wall and having external dimensions equal to those of said first end wall, said second tubular sidewall being formed integrally with said second end wall and having external dimensions equal to those of said second end wall, said first sidewall being adapted to telescopically fit over said second sidewall in a close fitting relationship to form a composite sidewall of an assembled muffler can wherein said first and second sidewalls are of a sufficient length and are telescoped within one another a sufi'rcient distance to provide a double wall thickness over substantially the full length of the mufller can with said first and second end walls disposed at opposite ends of said can, at least one tubular baffle wall formed integrally with and extending from said first end wall towards said second end wall and terminating short of said second end wall, at least one tubular baffle wall formed integrally with and extending from said second end wall towards said first end wall and tenninating short of said first end wall, said tubular bafile walls defining a continuous series of interconnected baffle paths in said casing that progresses radially outwardly of a longitudinal axis through the center of said first end wall and said second end wall, an opening through said casing to one of said series of interconnected baf fle paths and an opening through said casing to a subsequent one of said series of interconnected baffle paths. 

1. A muffler can comprising an outer casing having a first end wall, a second end wall, a first tubular sidewall and a second tubular sidewall, said first tubular sidewall being formed integrally with said first end wall and having external dimensions equal to those of said first end wall, said second tubular sidewall being formed integrally with said second end wall and having external dimensions equal to those of said second end wall, said first sidewall being adapted to telescopically fit over said second sidewall in a close fitting relationship to form a composite sidewall of an assembled muffler can wherein said first and second sidewalls are of a sufficient length and are telescoped within one another a sufficient distance to provide a double wall thickness over substantially the full length of the muffler can with said first and second end walls disposed at opposite ends of said can, at least one tubular baffle wall formed integrally with and extending from said first end wall towards said second end wall and terminating short of said second end wall, at least one tubular baffle wall formed integrally with and extending from said second end wall towards said first end wall and terminating short of said first end wall, said tubular baffle walls defining a continuous series of interconnected baffle paths in said casing that progresses radially outwardly of a longitudinal axis through the center of said first end wall and said second end wall, an opening through said casing to one of said series of interconnected baffle paths and an opening through said casing to a subsequent one of said series of interconnected baffle paths. 